A boy playing with a homemade toy walks past an Oxfam sign in Corail, a camp for displaced people of the earthquake of 2010, on the outskirts of Port-au-Prince, Haiti, February 17, 2018. REUTERS/Andres Martinez Casares

The Charity Commission, which regulates charities in England and Wales, said it had received 1,100 reports of serious "safeguarding incidents" since the scandal broke in February - equivalent to the number of reports for the whole of 2016-2017.

It did not elaborate on the incidents but has previously said they included child abuse.

The aid world has come under intense scrutiny since the Times newspaper reported that Oxfam staff used sex workers in Haiti after the country's 2010 earthquake.

Reports have also surfaced of Syrian women being sexually exploited in return for aid and harassment of women in the head offices of global charities.

Britain's Secretary of State for International Development Penny Mordaunt arrives at 10 Downing Street in London, Britain, July 3, 2018. REUTERS/Simon Dawson

Mordaunt will host a global summit in London in October aimed at getting leading donors, humanitarian agencies and others to agree on measures to prevent sexual exploitation.

She told the inquiry by the International Development Committee that her department was drawing up proposals to share at the summit in consultation with abuse victims, who would have a central voice at the conference.

Mordaunt announced earlier this year that the government would not fund agencies who failed to get their houses in order.

A senior Department for International Development (DFID) official previously told the inquiry that "nothing is any longer in the 'too difficult' box".

One idea being floated is an "international humanitarian passport" which could be revoked if aid workers breached rules.

Mordaunt said she wanted to send a "powerful message" that aid recipients should feel able to speak up and that predatory individuals should leave the sector.

She said her department was working closely with the National Crime Agency which can investigate sexual offences committed outside the country.

"I understand that because of the action we have taken ... and the strong message we are sending ... that predatory individuals have moved out of the (aid) sector. There is some evidence that has happened," Mordaunt added.

She told the inquiry there was now a momentum to tackle the issue, led by Britain.

"I think we have made unprecedented progress, but we have to keep the pressure up," she added.

Mordaunt said agencies must ensure those who committed abuse were brought to justice and must not let staff "off the hook" because of concerns over the potential impact on fundraising.

But she agreed it was not always appropriate to report sexual abuse to national authorities, for example in places where a victim of rape could face repercussions.

The inquiry also heard that the World Bank had banned all staff from using prostitutes even if based in countries where prostitution is legal.

Our global editorial team of more than 50 journalists and about 250 freelancers covers the world’s under-reported stories at the heart of aid, development, women’s and LGBT+ rights, human trafficking, property rights, and climate change.